mumford



No. 616,580. Patented Dec. 27, I898. J. A. MUMFURD.

TOWING MACHINE.

(Application filed May 20, 189B.)

2 Sheets-Sheet I.

(No Model.)

W/TNESSES No. 6I6,580. Patented Dec. 27, I898.

J. A. MUMFORD.

TOWING MACHINE.

(Application filed may 20. 1898.)

2 Sheets-Sheet 2.

(No Model.)

WITNESSES BY $5M ATTORNEY.

JOSEPH A. -MUMFORD, OF IIANTSPORT, CANADA.

TOWING-MACHINE.

SPECIFICATION forming part of Letters Patent No. 616,580; dated December 27, 1898.

Application filed May 20, 1898.

To all whom it may concern.-

Be it known that I, J OSEPH A. MUMFORD, a citizen of the Dominion of Canada, residing at Hantsport, in the Province of Nova Scotia, in the Dominion of Canada, have invented new and useful Improvements in Towing-Machines, of which the following is a specification.

My invention relates to the method of attaching hawsers or tow-lines to vessels to be towed or to those that do the towing, especially to the class of heavy sea-going tugs and barges. It is known in the towing of this class of vessels, owing to rough seas and weather and other causes, that the tension of the tow-line is constantly varying and often becomes for short intervals too great for its strength, particularly when inelastic wire ropes are employed.

The object of my invention is to provide such an attachment of one end of the towline, or, in case of very long hawsers, both ends of the same, that when it (the towline) would otherwise suddenly become too much strained the point or points of attachment will yield or become sufficiently extended to relieve the dangerous or breaking stress of the hawser and when the temporary cause of the hazardous tension is passed the tow-line will again automatically return or be drawn back to its former or normal position and stress.

The nature of my invention consists of ad 3' usting and varying the force of thesteam or air pressure engine by means of a back-pressure valve in the exhaust-pipe thereof automatically connected with and controlled and operated by the movements of the engine, whereby the said valve and engine automatically and reciprocally control each other. This I accomplish by the mechanism illustrated in the accompanying drawings, in whiol1 Figure 1 represents a plan view; 2, a longitudinal or side elevation; Fig. 3, a transverse elevation or end view. 1

Similar designating-numerals refer to similar parts throughout the several views.

I will first state that the towing-machine consists of any of the well-known standard steam hoisting devices, preferably of the gear Serial No. 6 81,204. (No model) type, on the drum of which the fixed end of the hawser is fastened and on which it (the hawser) is coiled and uncoiled.

l 1 represent the framework or bed-plate of the towing-machine, which is fastened to the deck of the towing vessel or the vessel being towed; 2 2, the winding-drum of the towing-machine; 3 3, the steam-cylinders of the towing-machine; 4 4, steam-inlets to the cylinders; 5, the towing-hawser, partly coiled on the drum; 6 0, a back-pressure valve of the ordinary rolling-valve type or any other suitable valve set midway between the cylinders on the exhaust-pipes, both of which enter into the said valve; 7, an exhaust opening out of the bottom of exhaust back-pressure valve; 8 8, exhaust-pipes opening into exhaust back-pressure valve; 9, a spindle of the exhaust baelnpress u re valve; 10, a hand-lever secured to said valve-spindle; 11, a lever-block loose on the hub of the said hand-leveiywhich is keyed to the valvespindle; 12, a handwheel or look-nut to secure the said leverblock to the Valve-spindle; 13, an operatinglever pivoted on the said lever-block, so as to give it vertical freedom; 14, a grooved sheave in the working end of the said operating-lever and which said sheave rides and rotates on the hawser not far from the winding-drum. Having pointed out the various parts of my invention, I will now explain the function of each and describe their general operation.

By referring to Fig. 3 and considering the lock-nut to be set up by the hand-wheel 12 in any desired position it will be seen that if the operating-lever 13 be moved to and fro from rightto left and left to right it will operate the spindle of the exhaust back-pressure valve 6 6--in other words, that this operatinglever controls the said valve to more or less open and close it, corresponding to the extent and frequency of the movements of the said operating-lever. It will be seen also that the movable end of this lever will be controlled in its movements to and fro by the towing hawserfthat travels in the groove of the sheave 14, and that the hawser will move to and fro from right to left and left to right,accordingly ash; is being coiled on or uncoiled from the drum 2 2, and that the scope of this to-andfro movement of the hawser will depend upon the diameter of the hawser and the number of turns the drum makes either as the hawser is being coiled or uncoiled.

From the foregoing I can now clearly explain the general operation of my invention and show 110w it successfully accomplishes in this simple and inexpensive manner the object previously set forth.

Supposing under favorable conditions of sea and weather a given tow of vessels requires a given steady tension or stress on the towinghawser, the full force of the steam-pressu re is now turned on, which gives the engine a surplus of power, or more force than is required to maintain the said steady tension on the hawser, whereupon I diminish the force or power of the engine until it equals or balances the said needed steady stress on the hawser, which I do only by setting and fastening on its spindle the back-pressure valve in such a position as will reduce the force of the engine to the degree of tension that equals and balances the said steady stress on the hawser. If now from whatever cause an extra or hazardous stress is thrown upon the hawser, it will begin to pay out, and thus be relieved of the dangerous strain, and as it gradually runs off of the drum its lateral movement, caused by its uncoiling, will correspondingly act upon and increase the opening in the back-pressure valvein the exhaustpipe, which will give a corresponding increase of power to the engine or allow it (the engine) to exert more force, and this extra force of the engine will now draw back the hawser before it pays out too far, and thereby correspondingly close the exhaust back-pressure valve until the power or force of the engine again becomes sufficiently diminished to correspond to and balance the said normal steady stress or draft on the hawser.

There is an additional advantage resulting from my device in that the cylinders of the engine are kept hotter, never being allowed to cool down to the atmospheric temperature.

It will be seen that my device is very simple of construction, as well as efficient, and conveniently adjustable to various degrees of hawser tension, as it consists only in the addition to an ordinary steam towing-machine of the adjustable back-pressure valve on the exhaust-pipe of the engine and utilizing by any ordinary suitable mechanism the lateral to-and-fro motion of the hawser on the winding-drum to automatically control the said valve.

The margin of difference between the force of the engine under full pressure of steam and when diminished by the partially-closed back-pressure valve can be made more or less by the set or position of the said valve, to-

gether with the rapidity or slowness of its au= tomatic action, whereby the hawser can be allowed to pay out and be drawn back to any desired extent, as circumstances may require, even embracing a scope of from five feet to a hundred feet or more, if necessary.

I wish it to be distinctly understood, however, that I do not limit myself to the exact method described or to any other particular mechanism for connecting the lateral to-andfro movement of the hawser on the windingdrum with the exhaust back-pressure valve, as various contrivances may be devised for this purpose.

I wish it further understood that I do not limit myself to either of the methods shown and described or to any other particular mechanism for'controlling and operating the backpressure valve in the exhaust-pipe by the movements in the engine, whereby a reciprocal and automatic action is established between the movements of the engine and the said valve, as different and ordinary mechanism can be employed for this purpose.

I am aware that back=pressure valves in the exhaust pipes or ports of steam-engines have been employed, but I am not aware that they have been used as and for the purpose herein set forth; therefore What I claim as new and useful, and desire to secure by Letters Patent, is-

1. In a steam towing-machine, a back-pressure valve in the exhaust-pipe of the engine, a winding-drum connected to the engine a hawser wound thereon and connection between the valve and hawser, whereby the uncoiling of the hawser from the drum will antomatically more or less open the said valve and the recoiling of the hawser on the drum will automatically more or less close the said valve, substantially as and for the purpose described.

2. In a steam towing-machine, a back-pressure valve in the exhaust-pipe of the engine, a winding-drum connected to the engine a hawser wound thereon and automatic connection between the said valve and hawser, whereby the lateral to-and-fro movement of the hawser, caused by the partial unwinding and recoiling of the same, will gradually and automatically open the said valve and thereby give the engine greater power, under the same pressure of steam, to sustain greater strain of and recoil the hawser on the drum when the extra strain is removed therefrom, as and for the purpose described.

JOSEPH A. MUMFORD.

-Witnesses:

C. H. J AOOBUS, E. H. GoURLEY,

IIO 

